Textile thread heating apparatus



Sept 7, 1965 J G. D. MANWARING 3,205,334

TEXTILE THREAD HEATING APPARATUS Filed July 30, 1963 United StatesPatent 3,205,334 TEXTILE THREAD HEATING APPARATUS Joshua G. D.Manwaring, Needham, Mass., assignor to Radio Frequency Company Inc.,Medfield, Mass., a corporation of Massachusetts Filed July 30, 1963,Ser. No. 298,626 2 Claims. (Cl. 219-10.61)

This invention relates to apparatus for continuous heat treatment of anelongated moving textile filament or thread by means of a radiofrequency field. Throughout this specification, the terms thread andfilament will be used interchangeably and are intended to includetextile monofilament as well as roving, yarn, or thread composed ofnatural or artificial fibers. Particularly, this invention relates tothe heating of textile threads such as rayon, nylon and the like by ahigh frequency electric field, continuously as the threads are producedor processed and moved longitudinally, and is concerned with improvedelements for applying the field to the moving thread.

One object of the invention is to provide such a heater with elementsthat may serve as guides and supports for the textile filament and thatwill not impede free longitudinal movement of the thread at usualproduction or processing speeds. Incidentally such freedom of movementwill allow the thread to expand or contract during heating.

A further object is to provide a heater of the character described thatis easy to make, economical to operate and desirably uniform in itsheating action on the moving thread or filament.

Still another object: of the invention is to provide, for a continuouslymoving filament, a radio frequency heater with electrodes that arelargely free from any tendency pair being connected to one side of aradio frequency,

oscillating circuit, the legs of the other U in the pair being Connectedto the other side of the radio frequency oscillator. These threadguiding and supporting electrodes are physically arranged with one legof each U intermeshing or alternating with one leg of the other U in apair, and the U-pieces are also positioned with their legs and bent endsextending upwardly. in planes crossing each other to form an X whenviewed from one direction, edgewise of the pair of electrodes. Themoving thread or filament to be heated lies Within and may be supportedand guided across the pair of crossed electrodes at or close to thecrotch or cross-over point of the X, passing close to first one leg of afirst electrode, then one leg of the second electrode, then the otherleg of the first electrode and finally the other leg of the secondelectrode in each pair. Beyond a first pair of electrodes, further pairsof identical electrodes may be mounted in horizontally aligned relationso that the thread travels past and is in close proximity alternatelyand successively to a multiplicity of electrodes of dilferentpolarities.

Other objects and further details of that which is believed to be noveland included in this invention Will be clear from the followingdescription and claims, taken with the accompanying drawing in which isillustrated an example of textile thread or filament heater embodyingthe present invention and incorporating pairs of crisscrossed U-shapedthread guiding and supporting electrodes described generally above.

In the drawings:

FIG. 1 is a top plan view of a section of a thread guiding, supportingand heating assembly according to this invention;

FIG. 2 is a transverse vertical sectional view therethroughsubstantially on the line and in the direction of the arrows 22 of FIG.1, showing diagrammatically certain electrical connections that may bemade thereto, and

FIG. 3 is an endwise top perspective view of one pair of the threadheating electrodes showing how a textile thread or filament is guidedand supported therein.

In carrying out the objects of this invention, in one embodimentthereof, radio frequency current is imposed on and induced in alongitudinally moving filament F by traversing the filament continuouslyover and near to or in contact with a series of electrodes that maysupport and guide the filament. The particular design, arrangement andmounting of these thread heating electrodes are the characteristicfeatures of this invention.

Accordingly, a V-shaped skeleton trough is made up of one or more pairsof cross-wise arranged inverted U- shaped round wire pieces. Thesepieces are intended as paired electrodes indicated by the numbers 10 and11 through 20 and 21 inclusive, the even numbers representing electrodesof one polarity and the odd numbers indicating electrodes of oppositepolarity as will later appear. Each of these rounded Wire electrodepieces is substan tiallyidentical with all others, and to form the U,each includes parallel leg portions 22 joined at one end by asimi-circular bight or bend 24.

Considering a single pair of electrodes, because they are arranged inidentical sets of pairs, the even-numbered electrode is suitably securedmechanically and electrically at the ends of both its legs to anelongated feeder strip or bus bar 26, and the odd-numbered electrode ofeach pair is similarly secured in any suitable fashion to an opposingfeeder strip or bus bar 27, these bus bars preferably being given achannel shape as indicated in FIG. 2 of the drawing and having parallelclosely spaced longitudinal facing walls 28 and 29 as shown in thatfigure.

The bent ends of the electrodes of each pair are extended upwardly fromtheir respective supporting feeder strips, as shown, and at an angle toeach other so that the legs of the pieces cross and form an X as seen inend view, FIG. 2. One leg of each U-piece in each pair is locatedbetween and spaced equally fromthe legs of the other U-piece of thepair, looking downwardly as in FIG. 1.

Electrical connections are made through the bus bars 26 and 27 to therespective electrodes in each pair, the bus bar 26 being connected toone output side 30 of a radio frequency oscillator 32 and the other busbar 27 being connected to the other output side 31 of the oscillator. Asan example of frequencies found useful, but not limiting the inventionin any sense, the oscillator may operate in the range of from 10 to 100megacycles and upwards. 1

Suitable driving power source connections are provided for theoscillatorthrough leads such as 34 in a customary fashion.

To extend the heating area a multiplicity of pairs 0 the crossed,U-shaped electrodes are mounted on the 1 adjacent pair as the crossedlegs of each individual pair i are spaced from each other.

Therefore, as long as the assembly of electrodes may extend, the movingfilament or thread will contact electrically or be influenced by firstan electrode of one'polarity and then an electrode of opposite polarityat equally spaced points. The arrange ment is such that a radiofrequency field is created between the crossed legs of adjacentelectrodes within each pair and between pairs, this field having itshighest intensity in the spaces betweenthe electrodes where the legscross each, other. Because the thread or filament is moving lengthwisewithin the skeleton trough formed by the crossing of the legs of theelectrodes it is located and traveling in the field virtually entirelyin the area of highest intensity. By thus arranging a number ofelectrode pairs seriatum with their crossing points alignedhorizontally, the efficiency of the individual guiding and supportingelectrode pairs is increased or improved.

Speaking geometrically, the pairs of electrodes may be described ascomprising two identically formed members, each having two straight,elongated, spaced legs defining a plane, joined together by a curvedportion at one end spanning the space between the legs, said membersbeing oriented relative to each other so that a leg of each one passescentrally between both legs of the other and so that the planes definedby the legs of the members intersect, preferably at about 90 degrees onefrom the other, in a single line of intersection passing through bothlegs of both members of the pair. The line of intersection of the legsof the crossed members includes the points where electrodes of onepolarity most closely approach those of the opposite polarity andtherefore is the line or center of highest intensity of the radiofrequency field between the electrodes. If the crossing of electrodes ismade to depart substantially from the preferred 90 degrees mentionedabove, the field between adjacent electrode members of differingpolarity may become undesirably dis persed or spread over a larger areaand its effect therefore weakened accordingly.

The heating effect and eificiency of the apparatus is further benefittedby the close and parallel spacing of the opposed walls 28 and 2% of thefeeder members, these creating a condenser action immediately below themving thread which adds to the capacitance of the load. The length ofthe bus bar or feeder members may be extended and the number of pairs ofthe U-shaped intermeshed electrodes multiplied to obtain any desiredelongation of the heating area.

Because the electrodes support and guide the thread at frequent andregular horizontal intervals, tension on the thread may be kept as smallas possible and still allow it to keep moving, thus permitting thematerial of the thread to contract freely during heating. The roundcross-section of the Wires forming the electrodes offers no resistanceto movement of the filament thereover, and

will not snag or catch on the moving thread even though this may be of aroughened or irregular conformation or texture on its outer surfaces.

Each individual wire piece serves as two electrodes of the same polaritybecause of the alternating crossed-over legs of each pair of electrodes.The tendency for arcs to be thrown from the electrodes is reduced to aminimum because the rounded cross-section of the wires and the curved orbent semi-circular end of each electrode piece provide no sharp pointsfrom which such arcs may start. If desired, any sharp corners on theedges of the opposed faces of the feeder bus bars may also be rounded toreduce possible arcing.

With the electrode mounting arrangement here shown and described it isalso possible to use the feeder bus and electrode assembly as its ownoscillating tank or radio frequency resonant circuit for example, in amanner according to my United States patent application, Serial No.275,417, filed April 24, 1963.

As will be evident from the foregoing description, certain aspects ofthis invention are not limited to the particular details set forth as anexample, and it is contemplated that various and other modifications andapplications of the invention will occur to those skilled in the art. Itis therefore, intended that the appended claims shall cover suchmodifications and applications as do not depart from the true spirit andscope of the invention.

What is claimed as new and is desired to be secured by Letters Patent ofthe United States is:

1. Apparatus for supporting, guiding and heating a lengthwise movingtextile filament comprising a pair of spaced parallel feeder members,

a multiplicity of spaced pairs of identical wire elements supported bysaid feeder members, each element consisting of two straight, elongated,spaced leg portions defining a plane and an integral portion joiningsaid leg portions at one end, spanning the space between said legs,

said leg portions terminating free of each other at the other end,

said wire elements in each pair oriented each relative to the other sothat a leg of each element passes centrally between both legs of theother element and so that the planes defined by the legs of each elementare at an angle one to the other and cross in a single line ofintersection passing through both said legs of both said elements ineach pair, the line of intersection of each pair being aligned with theline of intersection of all other pairs,

whereby a textile filament is adapted to be supported and guided inlengthwise movement on said elements adjacent said line of intersectionin proximity to both legs of both elements in each pair,

one said feeder member secured to and supporting the free ends of theleg portions of one of said wire elements in each pair and connected tomeans providing the feeder member and the legs of one wire element ineach pair with a radio frequency of one polarity,

the other said feeder member secured to and supporting the free ends ofthe leg portions of the other said wire element in each pair andconnected to means providing the other feeder member and the legs of theother wire element in each pair with the same radio frequency ofopposite polarity,

whereby a radio frequency field is produced between said wire elementsat the aforesaid line of intersection for heating a textile filamentmoving therealong.

2. Apparatus for supporting, guiding and heating a lengthwise movingtextile thread comprising a pair of straight, elongated, spacedhorizontal and parallel bus bars,

a multiplicity of identical pairs of round wire elements,

each element of each pair consisting of two straight, elongated, spacedparallel leg portions defining a plane and an integral semi-circularcurved portion joining said leg portions at one end, spanning the spacebetween said legs,

said leg portions of each element terminating free of each other at theother end and secured to one of said bus bars, the leg portions of theother element of each pair being secured to the other of said bus bars,

said wire elements of each pair oriented each relative to the other sothat a leg of each element passes centrally between both legs of theother element and so that the planes defined by the legs of each elementare at an angle one to the other and cross in a single line ofintersection passing through both said legs of both said elements in apair,

said pairs of elements being mounted in longitudinally spaced relationon said bus bars with their lines of intersection aligned,

whereby a textile thread is adapted to be supported and guided on saidmultiplicity of pairs of elements for lengthwise movement substantiallyalong said lines of intersection in proximity alternately to legs of theelements in all pairs,

means providing one bus bar and the legs of one element of each pairwith a radio frequency of one polarity, and means providing the otherbus bar and the alternating legs of the other elements of the pairs withthe same radio frequency, but of opposite polarity,

whereby a radio frequency field is produced at the aforesaid line ofintersection between said elements in each pair and between adjacentpairs of ele- UNITED STATES PATENTS 2,479,353 8/49 Hansell 219l0.612,685,745 8/54 Wakefield 219-l0.6l 2,960,777 11/60 Doll 219-10.61

RICHARD M. WOOD, Primary Examiner.

1. APPARATUS FOR SUPPORTING, GUIDING AND HEATING A LENGTHWISE MOVINGTEXTILE FILAMENT COMPRISING A PAIR OF SPACED PARALLEL FEEDER MEMBERS, AMULTIPLICITY OF SPACED PAIRS OF IDENTICAL WIRE ELEMENTS SUPPORTED BYSAID FEEDER MEMBERS, EACH ELEMENT CONSISTING OF TWO STRAIGHT, ELONGATED,SPACED LEG PORTIONS DEFINING A PLANE AND AN INTEGRAL PORTION JOININGSAID LEG PORTIONS AT ONE END, SPANNING THE SPECE BETWEEN SAID LEGS, SAIDLEG PORTIONS TERMINATING FREE OF EACH OTHER AT THE OTHER END, SAID WIREELEMENTS IN EACH PAIR ORIENTED EACH RELATIVE TO THE OTHER SO THAT A LEGOF EACH ELEMENT PASSES CENTRALLY BETWEEN BOTH LEGS OF THE OTHER ELEMENTAND SO THAT THE PLANES DEFINED BY THE LEGS OF EACH ELEMENT ARE AT ANANGLE ONE TO THE OTHER AND CROSS IN A SINGLE LINE OF INTERSECTIONPASSING THROUGH BOTH SAID LEGS OF BOTH SAID ELEMENTS IN EACH PAIR, THELINE OF INTERSECTION OF EACH PAIR BEING ALIGNED WITH THE LINE OFINTERSECTION OF ALL OTHER PAIRS, WHEREBY A TEXTILE FILAMENT IS ADAPTEDTO BE SUPPORTED AND GUIDED IN LENGTHWISE MOVEMENT ON SAID ELEMENTSADJACENT SAID LINE OF INTERSECTION IN PROXIMITY TO BOTH LEGS OF BOTHELEMENTS IN EACH PAIR, ONE SAID FEEDER MEMBER SECURED TO AND SUPPORTINGTHE FREE ENDS OF THE LEG PORTIONS OF ONE OF SAID WIRE ELEMENTS IN EACHPAIR AND CONNECTED TO MEANS PROVIDING THE FEEDER MEMBER AND THE LEGS OFONE WIRE ELEMENT IN EACH PAIR WITH A RADIO FREUENCY OF ONE POLARITY, THEOTHER SAID FEEDER MEMBER SECURED TO AND SUPPORTING THE FREE ENDS OF THELEG PORTIONS OF THE OTHER SAID WIRE ELEMENT IN EACH PAIR AND CONNECTEDTO MEANS PROVIDING THE OTHER FEEDER MEMBER AND THE LEGS OF THE OTHERWISE ELEMENT IN EACH PAIR WITH THE SAME RADIO FREUENCY OF OPPOSITEPOLARITY, WHREBY A RADIO FREQUENCY FIELD IS PRODUCED BETWEEN SAID WIREELEMENTS AT THE AFORESAID LINE OF INTERSECTION FOR HEATING A TEXTILEFILAMENT MOVING THEREALONG.